1. Field of the Invention
This invention relates to a junction structure between a steel member and a structural member, and more particularly, to a junction structure between a steel member and a structural member utilizing junction hardware arranged on the steel member and a metal connector arranged on the structural member. In this invention, the steel member includes a steel beam whereas the structural member includes a reinforced concrete column, a steel framed concrete column or a steel column.
2. Description of the Prior Art
In case the steel member is a beam and the structural member is either a reinforced concrete structure or a steel framed concrete structure column, a number of methods for connecting the steel beam to the column have been proposed and practiced as well. However, particularly, in case steels are provided in concrete and columns are in a steel frame reinforced concrete construction, a method has been generally applied that joint plates are crossed over between a diaphragm connected at a junction position of a steel column and a flange of a bracket of a steel beam or an edge portion thereof and connected by tightening bolts. In case the columns are in a reinforced concrete construction, there are representative methods: such as a method for connecting bolt-like junction hardware provided in the concrete and projected from side surfaces of the columns to the flange of the steel beam by tightening bolts, and another method for butting steel beams against the side surface of the concrete and connecting end plates matched to an end surface thereof to bolts buried into the concrete.
With reference to the method for connecting the steel beams to the steel column through the diaphragm, there are not so many advantages in building beams in a form of steel framed construction due to the similar arrangement of the junction between columns and beams in the normal steel framed reinforced concrete construction. In addition, there is a problem of insufficient concrete packing or filling in the concrete because the diaphragm blocks the section of the columns.
With respect to the method of using the bolt-like junction hardware having, at both ends thereof, the plate portions projecting from the side surface of the column, the concrete packing and the workability for the arrangement of column reinforcement are all satisfactory. However, as the plate portion expands to the beam side from the side surface of the column, the sizes of the steel beams facing one another across the column are limited, and in case the beams are mutually different, they cannot be applied and a step difference is produced between orthogonal junction hardware. Therefore, it is necessary to insert a filler plate so as to arrange the steel beams in orthogonal directions at the same level, and at the same time, it becomes difficult to site a bed type frame due to the generation of the step difference.
With reference to the method for butting the steel beams against the side surface of the column, after connecting the bolts buried into the column concrete in advance and projected from the side surface to the end plates, packing materials such as mortar are packed around this junction, but it is not suitable for the columns in a poured-in-place concrete construction because it will become necessary to position the bolts. In addition, as a step difference is produced between orthogonal bolts, there is a similar problem to that in case of using the junction hardware, and at the same time, the positions of the bolt holes of the hardware such as end plates connected to beam edge portions differ in an orthogonal direction to bring about the complication in processing the hardware.
In case the columns are built in a steel framed construction, a method for inserting diaphragms into the upper and lower flange positions of the steel beams in the steel column for the smooth transmission of the stress from the steel beams and the reinforcement of the steel column is generally employed.
The basic arrangement of the diaphragms in this case is roughly divided into two forms: a form of inserting them into the inside of the flange in the steel column and another form of protruding them into the external circumferences.
In case the steel column having a closed cross-section such as those of square steel pipes and is packed with concrete in an internal portion thereof to give the column in a steel framed concrete construction or in a steel framed reinforced concrete construction, there is a method for placing stiffeners vertically considering the concrete packing problem and a method for rolling band plates around the external circumference of the steel column, but a method by normally using diaphragms because of the dependability of stress transmission is general. In case the diaphragms get into the internal portion of the steel column, the sufficient packing of concrete is secured by making an opening in this.
In the method for inserting the diaphragm into the internal portion of the steel column, at least the portion of the junction is composed of box-like steel pipes in an assembled form or the steel pipes are once cut at the junction position, provided therein and the diaphragms are then welded to assemble. In any cases, the resulting assembling depends on welding, and therefore, particularly, due to a number of butted welding amounts, it takes a lot of labor and time to proceed the processing and assembling operation.
In the method for protruding the diaphragms into the external circumference, it becomes necessary to divide the diaphragm into a plurality of pieces resulting in an increase in the number of parts, and the amount to be welded is required in the same degree as that in case of inserting into the internal portion. Therefore, the complication in processing and assembling work cannot be avoided, similar to the internal diaphragm method.
In case the steel member is a column, in the method for rigidly connecting the column base in the steel column in a steel framed construction or a steel framed reinforced concrete construction to a concrete base as a structural member, the shearing force from the column base is normally transmitted by a frictional force between the lower surface of a base plate and a top edge surface of the concrete base, and in case of exceeding the frictional force, the shearing force is borne by the shearing strength of anchor bolts. In case the shearing force particularly becomes excessive, however, the number of the anchor bolts or the total sectional area for the anchor bolts will have to be increased. However, a problem still remains because there is a limit in the number of anchor bolts available on the base plate which is determined by the minimum space requirements for clamping the bolts.
The present invention has been made on the basis of an understanding of all of the problems involving the junction between a steel member and a structural member such as a concrete member or the like, as well as the junction between the above-described steel beam and the column in a reinforced concrete construction, a steel framed concrete construction or a steel framed construction. Therefore, the present invention aims to newly propose a construction for overcoming the issues of the constructions in the prior art.